1. Field of the Invention
The present invention relates to a liquid injection head for injecting liquid from a nozzle injection port to record images and characters on a recording medium, a liquid injection recording apparatus, and a method of filling a liquid injection head with liquid.
2. Description of the Related Art
In general, a liquid injection recording apparatus, for example, an inkjet printer that performs various kinds of printings includes a conveying device that conveys a recording medium and an inkjet head. As one used in the inkjet printer, there is known an inkjet head which includes a nozzle body having a nozzle string including a plurality of nozzle holes, a plurality of pressure generating chambers that are paired with the respective nozzle holes and communicated to the nozzle holes, an ink supply system that supplies ink to the pressure generating chambers, and a piezoelectric actuator placed adjacent to the pressure generating chambers. In the inkjet head, the piezoelectric actuator is driven to pressurize the pressure generating chambers, thereby injecting ink in each of the pressure generating chambers from a nozzle injection port of each of the nozzle holes.
As one type, there is known an inkjet printer which includes a carriage for moving the inkjet head in a direction orthogonal to a conveying direction of a recording sheet (recording medium) and prints the recording sheet. In this type of inkjet printer, a service station for maintenance is provided in a movable range of the inkjet head, and the inkjet head is moved to the service station, whereby the nozzle holes are cleaned and the nozzle holes are initially filled with ink under suction with a cap being placed on the inkjet head.
Further, as a type different from the above-mentioned inkjet printer, there is an inkjet printer which is used for a relatively large recording medium such as a box or the like and prints a recording medium conveyed with an inkjet head being fixed. In this type of inkjet printer, an inkjet head can not be moved, and there is merely a small space for providing a service station between the inkjet head and the recording medium and below the inkjet head. Therefore, when a pressure generating chamber is initially filled with ink, ink is generally supplied from an ink supply system side under pressure.
During filling under pressure, in order to prevent the inkjet head and a vicinity of an inkjet printer from being contaminated with excess ink flowing from the nozzle holes and to prevent the injection of ink after the filling with the ink from being unstable, means for removing excess ink should be considered. Further, this also applies to the case of collecting ink flowing onto a nozzle body during an ordinary use, as well as the case of the initial filling.
JP 05-116338 A discloses an inkjet head in which an ink guide member protruding outward from a nozzle formation surface made of a plate porous absorbent and a block-type ink absorbent connected to the ink guide member are provided below the inkjet head, and the ink guide member receives excess ink and guides it to the ink absorbent so that the ink absorbent absorbs the guided excess ink.
However, according to the related art, the ink guide member and the ink absorbent are provided below the inkjet head. Therefore, there is a problem that the lower part of the inkjet head can not be used effectively. There is another problem that, in the case where an inkjet printer is designed under a predetermined constraint, a lower part of a recording medium can not be printed.
Further, according to the related art, an ink absorbent is allowed to merely absorb excess ink, and hence there is a limit to the amount of excess ink that can be collected.